In Iran's Factories and Shops, Tighter Sanctions Exact Toll

Congress passed new sanctions this week, signed by President Barack Obama, that lawmakers said move closer to a nearly complete trade embargo on Iran. The law seeks to block Tehran's ability to barter its oil for gold and precious metals, and significantly widens the number of Iranian energy, shipping and financial entities on the U.S. blacklist, and bars foreign firms from doing business with them.

"The sanctions so far have inflicted far greater damage on Iran's economy than anyone expected, but the economic pressure is still moving too slowly given the pace of Iran's nuclear development," said Mark Dubowitz of the Foundation for Defense of Democracies, a conservative Washington think tank that advised Congress on implementing the latest sanctions.

White House officials on Thursday declined to comment on how they are specifically going to implement the new sanctions, but said that the Obama administration has dramatically increased financial pressure on Tehran over the past four years.